OpenStax-CNX module: m20296
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Plant adaptations
∗
Siyavula Uploaders
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Creative Commons Attribution License 3.0
1 NATURAL SCIENCES
2 Grade 8
3 BIODIVERSITY
4 Module 28
5 PLANT ADAPTATIONS
Like animals, plants have also made adaptations to survive under particular climatic conditions.
As water is of utmost importance for the survival of plants, their adaptations are related to the availability
of water. Plants can be divided into three groups with regard to this type of adaptation.
•
•
•
minimal availability of water
moderate availability of water as with most plants growing on land
HYDROPHYTES maximal availability of water
XEROPHYTES
MESOPHYTES
5.1 Activity: TO CLASSIFY PLANTS
Study the following sketches and classify the plants according to their structures as hydro-, meso- or xerophytes. Attempt to provide at least one reason for your classication in each instance.
Figure 1
∗ Version
1.1: Mar 12, 2009 12:37 pm -0500
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Figure 2
Figure 3
5.2 Activity: TO EXPLAIN THE WAY IN WHICH SOME PLANTS ADAPT
HYDROPHYTE ADAPTATION EXPLANATION
Roots Poorly developed, only for anchoring
Leaves Large surface
Floating Cuticle (waxy layer) on surface
Air pockets in leaf
Stomata (small openings) on top
Stems
Very little strengthening tissue
Slimy layer
Rhizome (stores food)
XEROPHYTE ADAPTATION EXPLANATION
Roots
Shallow root system
Corky layer
Leaves
Few stomata, mainly on underside
Small or converted to thorns
StemsThick and eshy
Waxy layer
Could you supply correct explanations for each adaptation?
Assessment of assignment: [LO 2.4]
5.3 ASSIGNMENT: Story
The San most probably were the rst people to live in Southern Africa and we still think of their ability to
survive such dry conditions with astonishment. Water was a very limited resource.
But we do not have to go very far to discover some of the solutions that the San found centuries ago in
nature and in plants (xerophytes), in particular.
Read about the natural vegetation of the desert-like parts of our country.
Write a story about the survival of a plant in the Kalahari Desert. Write this from the point of view of
the plant. Let the plant do the talking to describe the conditions and how it manages to survive, and how it
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helps other plants, the San and animals to survive (its role in the food chain). Refer to the San people and
how they used plants to survive.
Assessment of assignment:
5.4 Could you write a factually correct story about San culture and the Kalahari ecosystem?
[LO 3.1]
5.5 Class Activity: Adaptations in xerophytes
Figure 4
Figure 5
Figure 6
Figure 7
Examine the sketches of these unusual xerophytes which adaptations do they exhibit?
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ALOE
CACTUS
LITHOPS
WELWITCHIA
Match the items in the following columns by writing the letters from COLUMN C in the appropriate
spaces in COLUMN B. More than one match is possible.
[LO 2.4]
6 Activity: TO CONDUCT A RESEARCH PROJECT
Most xerophytes are used as medicine and for a variety of other purposes in dierent cultures. Even primitive
cultural groups practised science thousands of years ago by determining the value of plants and nding ways
to use them.
Do research on the Internet, in books and in libraries.
Write a research report, using the following headings:
• Planning of the investigation (which has to include research through the Internet and books and
through conversations with homeopaths and sangomas or inyangas, as well as one or two older people).
• Information gathered:
Examples of the use of plants by cultural groups in South Africa.
Discussion of three specic plants, including the aloe (Aloe verox) (characteristics of the plants and
medicinal, economic or other value).
• Summary (summary of ndings)
• List of references: books, web addresses, and persons.
Assessment of RESEARCH PROJECT:
[LO 1.1; LO 1.2; LO 1.3]
7 Assessment
Learning outcomes 1: Scientic investigations
The learner will be able to act condently on curiosity about natural phenomena, and to investigate
relationships and solve problems in scientic, technological and environmental contexts.
This is evident when the learner
1.1 is able to plan investigations;
1.2 is able to conduct an investigation and collect data;
1.3 is able to evaluate data and communicate ndings.
Learning outcomes 2: Constructing Science Knowledge
The learner will know and be able to interpret and apply scientic, technological and environmental
knowledge.
This is evident when the learner
2.4 is able to apply knowledge.
Learning outcomes 3: Science, society and the environment
The learner will be able to demonstrate an understanding of the interrelationships between science and
technology, society and the environment.
This is evident when the learner
3.1 is able to understand science as a human endeavour.
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8 Memorandum
Activity: IDENTIFICATION: PLANTS
• www.lithop.supanet.com
Activity: EXPLAIN THE FOLLOWING ADAPTATIONS
ASSIGNMENT: Story
• Do some reading about the natural vegetation of the arid regions of our country.
• Write a story about the survival of an animal in the Kalahari Desert. Write this from the point of view
of the animal and from its situation in the food chain.
Class activity: XEROPHYTIC PLANTS ADAPTATIONS
ASSIGNMENT: Research project
• Most xerophytes are used as medicines and in a variety of other applications, by various cultural groups.
• The aloe ( Aloe ferox), in particular, has a wide range of applications consult homeopaths, sangomas
or an inyanga to nd information in this regard.
• Do research through the internet, books and libraries.
• Write a research report with the following headings as a guideline:
Growing regions
Special properties of the plant, especially the leaves
Medicinal and economic value of the plant
• Include a list of all the sources and websites that you consult.
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